Pancreatic cancer is one of the major causes of cancer death in Western countries. In 2010, an estimated 43,140 new cases of pancreatic cancer were diagnosed in the United States with an expected five year survival rate of less than about 10%. In about 20% of patients with no metastases, tumor resection is not feasible because of vascular invasion, poor general health, or lacking surgical techniques. The standard treatment for these patients is chemotherapy followed by chemo-radiation therapy, which results in a median survival of eight to twelve months or less.
Current therapeutic options for unresectable pancreatic cancer include radiofrequency ablation (RFA) and cryotherapy. As utilized in the treatment of pancreatic cancer, RFA risks thermal injury to important structures such as the bile duct, the duodenum, and vessels close to the pancreas. A major limitation with RFA is difficulty in assessing the ablated zone by ultrasound, magnetic resonance imaging (MRI) or computed tomography (CT) scan. The poorly perfused pancreatic area also makes it difficult to visualize. Further, studies have demonstrated that radiologic follow-up after ablation could not distinguish inflammatory reactions of the tumor tissue from tumor growth or necrosis within the first four weeks.
Studies have shown the effective use of cryoablation to treat pancreatic cancer via laparoscopic or transcutaneous approach with reduced side effects. Yet, broad based clinical utilization has been limited by commercial devices that do not provide adequate cooling power to effectively treat the cancerous tissue. The invasive nature of surgical (open or laparoscopic) access to the target also remains an ongoing issue along with technological limitations.
In addition, current cryoprobes as used in an endoscopic procedure can cause damage to the endoscope due to freezing of the catheter shaft to the inside of the endoscope. This can interfere with the ultrasound imaging and readjusting or removing the cryoprobe from the tissue or endoscope in a timely manner. Prolonged procedures also can cause freezing of the endoscope to surrounding tissue resulting in damage to non-target tissues such as the esophagus, stomach wall, colon, intestine, rectum or other structure.
For visualization of current pancreatic procedures, endoscopic ultrasound (EUS) has been utilized to image the pancreas in real-time. Issues related to laparoscopic ablation techniques, however, make imaging difficult. For example, anatomical location of the pancreas makes it difficult to visualize and access without damaging other tissues. Development of an effective EUS-guided catheter-based ablation device and treatment method could overcome the problems related to the laparotomy and/or laparoscopic or transcutaneous approaches.
The increasing incidence and high lethality of pancreatic cancer demands the development of new treatment options. An innovative effective endoscopic treatment option for pancreatic cancer would be minimally invasive while enhancing performance and outcome. The improved technology and methodology would reduce levels of disease recurrence, mortality, and damage to non-targeted tissue. Further, the technique would allow for selective ablation of tumor masses. The improved technique would also enhance efficacy of neoadjuvant treatment procedures in patients not suitable for any other kind of treatment. Endoscopic access compatibility would also be highly desired in combination with the use of ablative techniques to reduce procedure time, overall costs, and risks or other complications.
As desired, the improved therapeutic option will offer an effective, minimally invasive therapeutic option for gastroenterologists in the in situ treatment of pancreatic cancer or other gastrointestinal cancers or diseases. Furthermore, patients with any stage of pancreatic disease will benefit from the technology and technique. The treatment option will also reduce the five year mortality rate and reduce the U.S. annual estimated $1.4 billion in pancreatic therapy costs.
An improved endoscopic cryoablation catheter will be compatible with endoscopic instrumentation. Desirably, an EUS-guided cryoablation catheter will be integrally designed with the flexibility and stiffness necessary to place a probe directly though the stomach wall into the pancreatic tumor. The sharp needle-like tip of the probe will be capable of penetrating any desmoplasia, fibrous connective tissue, tumor infiltrate, and scar or fibrosis. Additionally, the sharpness of this needle-like probe can also be used for EUS guided pseudocyst drainage during the procedure. The EUS cryoablation procedure will provide surgeons with a minimally invasive tool that reduces morbidity and lowers costs.